Ejection device and imprint apparatus

ABSTRACT

Provided is an ejection device and an imprint apparatus which can suppress ejection failures and breakage of a mold. To achieve this, a circulation mechanism including a degassing unit is provided in an ejection head.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an ejection device and an imprintapparatus which eject an imprint material.

Description of the Related Art

Assume a case where a semiconductor device is to be fabricated by usingan imprint apparatus. In this case, since a pattern of a mold is fine,when an ejection failure occurs in an ejection device configured toeject an imprint material, thickness of the imprint material becomesuneven and filling for the mold decreases. Thus, a favorable patterncannot be sometimes formed. Hence, it is necessary to perform ejectionin a favorable manner in the ejection device.

Entrapment of air bubbles in a pressure chamber communicating withejection ports of an ejection head configured to eject the imprintmaterial can be given as one of causes for the ejection failure. Whenair bubbles are entrapped in the imprint material in the pressurechamber, the air bubbles function as air dampers and prevent ejection ofthe imprint material from the ejection ports and the ejection failureoccurs.

As a measure against generation of air bubbles in the pressure chamber,Japanese Patent Laid-Open No. 2006-095878 discloses a method in which adegassing unit is arranged near an ejection head and an imprint materialis circulated to reduce the amount of dissolved gas in the entireejection head.

SUMMARY OF THE INVENTION

An ejection device of the present invention is an ejection devicecomprising: ejecting unit for ejecting an imprint material to which apattern of a mold is transferred by bringing the mold into contact withthe imprint material; and containing unit including a first spacecontaining the imprint material and a second space separated from thefirst space by a flexible member, the first space communicating with theejecting unit, wherein the containing unit includes: a first openingwhich communicates with the first space; a second opening whichcommunicates with the first space; connecting unit for allowing theimprint material to move between the first opening and the secondopening; pump unit, provided in the connecting unit, for moving theimprint material between the first opening and the second opening; anddegassing unit, provided in the connecting unit, for collecting gasdissolved in the imprint material.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating an imprint apparatus employing an ejectionhead;

FIG. 2 is a view illustrating the ejection head and a pressure controlmember;

FIG. 3 is a cross-sectional view illustrating an inside of the ejectionmember in such a way that the viewer can see it;

FIG. 4 is a cross-sectional view of the ejection head;

FIG. 5 is a cross-sectional view illustrating the ejection head; and

FIG. 6 is a view illustrating a state where ejection heads are connectedin parallel to be stored.

DESCRIPTION OF THE EMBODIMENTS

However, in the method of Japanese Patent Laid-Open No. 2006-095878, apipe of a circulation system needs to be connected every time acartridge is replaced. When the pipe of the circulation system isconnected, a coupling and the pipe are rubbed and particles are therebygenerated. Mixing of foreign objects in the imprint material may causebreakage of the mold.

Accordingly, the present invention provides an ejection device and animprint apparatus which can suppress ejection failures and breakage of amold.

First Embodiment

A first embodiment of the present invention is described below withreference to the drawings.

FIG. 1 is a view illustrating an imprint apparatus 100 employing anejection device 101 of the embodiment. The imprint apparatus 100includes an ejection unit and an imprint unit. An imprint material 8ejected from an ejection member 11 of the ejection unit (ejection device101) is brought into contact with a mold in the imprint unit (processingdevice) and, in this state, is cured by being irradiated with anultraviolet ray from an ultraviolet ray emitting device 7. Note that, inthis embodiment, description is given of an example of a device whichuses a UV curable resin as the imprint material 8 and which cures the UVcurable resin by emitting the ultraviolet ray. However, the material andmethod of curing the imprint material 8 are not limited to thosedescribed above. For example, a light emitting device may emit a lightwith a wavelength other than ultraviolet to cure a light curable resin.Alternatively, a thermosetting resin may be used and be cured by beingheated.

The ejection device 101 includes an ejection head 10 which is formed ofthe ejection member 11 and a containing member 12 and a pressure controlmember 13 which is capable of controlling a pressure inside the ejectionhead 10. A substrate 4 is installed on a stage 6 and the imprintmaterial 8 is ejected from the ejection member 11 onto the substrate 4.The imprint material 8 ejected onto the substrate is cured by beingirradiated with the ultraviolet ray from the ultraviolet ray emittingdevice 7 while being brought into contact with the mold 1. A fine recessand protrusion pattern and the like are formed on the mold 1. When themold 1 is moved to a position above the ejected imprint material 8 andbrought into contact therewith, the pattern of the mold 1 is transferredto the imprint material 8. As described above, the imprint material 8 iscured by using the ultraviolet ray with the pattern of the mold 1transferred thereto.

The ejection head 10 is detachable and attachable. When all imprintmaterial 8 in the ejection head 10 is consumed, the ejection head 10 isreplaced by a new ejection head 10 and the new ejection head 10 ejectsthe imprint material 8 again as the ejection device 101.

The stage 6 can be moved on a base frame 5 while holding the substrate4. A mold drive mechanism 2 which moves the mold 1 up and down is heldon a structure 3 and can bring the mold 1 close to the substrate 4 andbring the mold 1 into contact with the imprint material 8. Theultraviolet ray emitting device 7 is provided above the mold 1 and emitsthe ultraviolet ray 9 to the imprint material 8 through the mold 1. Alight source of the ultraviolet ray 9 may be a light source such as, forexample, a halogen lamp which emits an I-line or G-line ray. Moreover,the ultraviolet ray emitting device 7 may have a function of focusingand shaping light generated by the light source.

Next, imprint operations are described. First, in the imprintoperations, the substrate 4 is mounted on the stage 6. The substrate 4is moved to a position below the ejection member 11 of the ejection head10 by using the stage 6. Then, the imprint material 8 is ejected fromthe ejection member 11 onto the substrate 4 while the stage 6 is moved.Then, a portion of the substrate 4 where the imprint material 8 isejected is moved to a position below the mold 1 by using the stage 6.Moreover, the mold 1 is lowered by the mold drive mechanism 2 andbrought close to the substrate 4. In this state, the positions of themold 1 and the substrate 4 relative to each other are adjusted byaligning an alignment mark on the mold 1 with an alignment mark on thesubstrate by using an alignment scope or the like. After the adjustmentof the positions, the mold 1 is further lowered (toward the substrate 4)by the mold drive mechanism 2 and thereby brought into contact with theimprint material 8.

After the imprint material 8 and the mold 1 are brought into contactwith each other, the ultraviolet ray 9 is emitted from the ultravioletray emitting device 7 and the imprint material 8 is irradiated with theultraviolet ray 9 transmitted through the mold 1. A photocuring reactionof the imprint material 8 thereby occurs and the imprint material 8 iscured. Thereafter, the mold 1 is removed from the cured imprint material8 by the mold drive mechanism 2. In the steps as described above, apattern (patterned imprint material) is formed on the substrate 4.

In some cases, an imprint apparatus used for semiconductor manufacturingforms a pattern over an entire region of the substrate 4. However, inthe embodiment, the imprint apparatus repeats the series of imprintoperations while changing the region where the operations are performedon the substrate.

FIG. 2 is a view illustrating the ejection head 10 and the pressurecontrol member 13. The ejection head 10 is described below. The ejectionhead 10 includes the ejection member 11 and the containing member 12 andis connected to the pressure control member 13 via a pipe 17 by using acoupling 56. The inside of the containing member 12 is divided into acontaining portion 15 and a filling liquid portion 16 by a separationfilm 14 which is a flexible member. The thickness of the separation film14 is preferably 10 μm or more and 200 μm or less. The separation film14 is preferably made of a material with low gas and liquid permeabilityand is made of, for example, a multilayer aluminum film. Out of thespaces formed by the separation film 14, the containing portion 15communicating with the ejection member 11 is filled with the imprintmaterial 8.

FIG. 3 is a cross-sectional view illustrating the inside of the ejectionmember 11 in such a way that the viewer can see it. The ejection member11 includes energy generation elements 29 which generate energy forejecting the imprint material 8. Moreover, the ejection member 11includes ejection ports 32 configured to eject the imprint material 8and pressure chambers 34 communicating with the ejection ports 32.Piezoelectric elements can be given as an example of the energygeneration elements 29. The energy generation elements 29 are controlledby a controller to generate pressure fluctuation in the pressurechambers 34 and thereby cause the imprint material 8 in the pressurechambers 34 to be ejected from the ejection ports 32 onto the substrate4.

Non-ejection can be given as an example of an ejection failure in theejection member 11 with such a structure. One of the causes foroccurrence of the non-ejection is entrapping of air bubbles in thepressure chambers 34. When air bubbles are entrapped in the imprintmaterial 8 in the pressure chambers 34, the air bubbles function as airdumpers in the ejection and the pressure fluctuation generated by theenergy generation elements 29 in the pressure chambers 34 is attenuated.As a result, no imprint material 8 is ejected from the ejection ports 32and the non-ejection occurs. The air bubbles are generated when a gasdissolved in the imprint material 8 in the pressure chambers 34 turnsinto air bubbles due to the pressure fluctuation in the ejection head orthe like. Moreover, in some cases, menisci of the imprint material 8largely vibrate in the ejection and air bubbles are taken into theimprint material 8. The air bubbles entrapped as described above causethe non-ejection.

There is a method of suppressing generation of air bubbles in which,upon filling the containing member 12 with the imprint material 8, thecontaining member 12 is filled with a degassed imprint material.However, a gas permeates resin members such as the containing member 12over time and the imprint material 8 at the ejection ports 32 comes intocontact with air. This causes the gas to dissolve into the imprintmaterial and the amount of gas dissolved in the imprint materialincreases over time.

The containing member 12 is formed of the containing portion 15 in whichthe imprint material 8 is housed and the filling liquid portion 16 inwhich a filling liquid is housed. The filling liquid portion 16 is aspace on the opposite side of the separation film 14 (flexible member)to the containing portion 15 and is a space not communicating with theejection member 11. The filling liquid portion 16 communicates with thepressure control member 13 via a filling liquid pipe 17. In attachingand detaching of the ejection head 10, separation and connection can beachieved by using the coupling 56. The pressure control member 13 isformed of a filling liquid tank, a pipe, a pressure sensor, a pump, avalve, and the like. The pressure sensor, the pump, and the valvecontrol the pressure of the filling liquid in the filling liquidportion. The pressure control member 13 controls the pressure of thefilling liquid to control the pressure of the imprint material 8 in thecontaining portion 15 via the separation film 14.

Controlling the pressure of the imprint material 8 in a state where theimprint material 8 is isolated from the outside as described above canstabilize the shapes of gas-liquid interfaces (menisci) in the ejectionmember 11 and enables ejection of the imprint material 8 with goodreproducibility. When the ejection of the imprint material 8 from theejection member 11 is repeated, the imprint material 8 in the containingportion 15 is consumed and decreases and the separation film 14 deforms.The pressure control member 13 supplies the filling liquid to thefilling liquid portion 16 with the deformation of the separation film 14and fills the filling liquid portion 16 with the filling liquid.

Note that the containing portion 15 may be a portion obtained by forminga flexible film being a separation film in a bag shape like an IV bag.Moreover, the containing portion 15 may be configured such that agas-liquid interface is provided in the containing portion 15.Furthermore, the containing portion 15 may be an atmosphere open type inwhich the containing portion 15 communicates with an atmospherecommunication port. When the containing portion 15 is the atmosphereopen type, a valve for switching between open and closed states(openable and closeable valve) and a device for controlling the pressureare preferably connected to the containing portion 15 to performnegative pressure control in a favorable manner.

In the field of an inkjet recording apparatus, ingenuities formaintaining the inside of the ejection member 11 within a certainnegative pressure range have been made to stabilize the shapes of themenisci at the ejection ports of the ejection member 11. For example,there is known a method in which a porous body is formed in thecontaining portion to hold the imprint material and the negativepressure is generated by utilizing the capillary force in the porousbody. Moreover, there are a method of generating the negative pressurein the containing portion by using a combination of a balloon-shapedfilm and a mechanical element such as a spring and a method ofcontrolling the negative pressure by using a control valve and an airpressure. In the present invention, the negative pressure in thecontaining portion may be controlled by using any of these methods.

FIG. 4 is a cross-sectional view illustrating the ejection head 10 inthe embodiment. The ejection head 10 in the embodiment includes acirculation mechanism which can cause the imprint material 8 inside theejection head 10 to circulate in the containing portion 15. Thecontaining portion 15 includes a first opening 20 and a second opening21 and a passage forming member 28 connecting these two openings arearranged. The first opening 20 is an opening for supplying the imprintmaterial 8 in the containing portion 15 into the passage forming member28. The second opening 21 is an opening for returning the imprintmaterial 8 supplied from the first opening 20 to the containing portion15. The passage forming member 28 is a passage of the imprint material.A pump 22 and a degassing unit 50 are arranged in the passage formingmember 28.

The degassing unit 50 includes a gas permeable film 51 and a cover 52surrounding the gas permeable film 51. A pipe extends from the cover 52and a coupling 53 is provided on the pipe. The members described aboveare configurations included in the ejection head 10. After the ejectionhead 10 is installed in the imprint apparatus 100, a discharge duct 54is connected to the coupling 53 to reduce the pressure in the spaceinside the cover 52 to about −90 KPa.

Since the gas permeable film 51 is permeable only to gas and is notpermeable to liquid, when the pressure in the cover 52 is reduced, thegas dissolved in the imprint material passes the gas permeable film 51and escapes into the cover 52. The concentration of the gas dissolved inthe imprint material thereby decreases. The imprint material with alower concentration of the dissolved gas enters the containing portion15 due to an operation of the pump 22. As a result, the amount of gasdissolved in the imprint material in the containing portion 15decreases.

Since the containing portion 15 communicates with common liquid chambers33 of the ejection member 11, a decrease in the amount of gas dissolvedin the imprint material in the containing portion 15 can cause theamount of dissolved gas in the common liquid chambers 33 to decrease.When the amount of dissolved gas in the common liquid chambers 33decreases, the dissolved gas in the pressure chambers 34 diffuses andthe amount of gas dissolved in the imprint material in the pressurechambers 34 decreases.

Moreover, since the amount of the dissolved gas in the pressure chambers34 has decreased, the air bubbles taken into the imprint material due tolarge vibration of the menisci in the ejection tend to dissolve into theimprint material. Accordingly, the air bubbles dissolve into the imprintmaterial over time and eventually disappear. The gas dissolved into theimprint material is collected by the degassing unit 50. Suppressing theentrapment of air bubbles in the pressure chambers 34 as described abovecan suppress occurrence of non-ejection caused by the air bubbles in theimprint material.

Note that the concentration of the dissolved gas in the common liquidchambers 33 can be reduced by causing the degassed imprint materialhaving passed the passage forming member 28 to flow to the common liquidchambers 33. Accordingly, the second opening 21 is preferably providednear the common liquid chambers 33, facing the common liquid chambers33. In other words, it is preferable that the distance from the secondopening 21 to the ejection member 11 is shorter than the distance fromthe first opening 20 to the ejection member 11.

The imprint material 8 used in the imprint apparatus 100 is required tocontain as little foreign objects (fine particles) and metal ions aspossible and to maintain its properties until application onto thesubstrate 4. In the present invention, the imprint material 8 is storedwhile being isolated from the outside of the containing portion 15 in aperiod in which the volume of the containing portion 15 decreases due torepeated ejection of the imprint material 8 and eventually all imprintmaterial 8 is consumed.

In the attaching and detaching of the ejection head 10, it is onlynecessary to attach and detach the filling liquid pipe 17 and thedischarge duct 54 of the degassing unit 50 and there is no need toattach and detach a flow passage on the imprint material side.Accordingly, the state where the imprint material is isolated from theoutside can be maintained also in the attaching and detaching of theejection head 10. As described above, in the embodiment, the imprintmaterial does not come into contact with the outside air and devicessuch as the pressure sensor from the moment when the ejection head 10 isattached and detached to the moment when the imprint material iscompletely consumed. Accordingly, it is possible to suppress an increaseof foreign objects and metal ions in the imprint material sealed in amanaged state in an initial stage.

Note that the passage forming member 28 of the ejection head 10 may beprovided with a filter 23. In some cases, the imprint material 8 turnsinto gel due to changes over time and the imprint material in thecontaining portion 15 needs to be filtered. Providing the filter 23 forfiltering the imprint material in the passage forming member 28 allowsthe circulation pump 22 for degassing to be used also for circulationfor filtering and cost and space can be reduced. Since there is apossibility of particles being generated in the pump 22, the filter 23is preferably provided downstream of the pump 22 to catch the particlesdownstream of the pump 22.

Moreover, the imprint apparatus 100 is required to highly accuratelycontrol the amount and landing position of the imprint material ejectedon the substrate. Accordingly, the shape of the meniscus at eachejection port 32 of the ejection member 11 needs to be stablymaintained. In the ejection head 10, the pressure of the imprintmaterial sometimes fluctuates due to drive of the pump 22. Accordingly,it is preferable to stop the drive of the pump 22 while the imprintmaterial 8 is ejected from the ejection head 10.

Furthermore, in the imprinting step, the pattern is formed in eachregion of the substrate by repeating the ejection of the imprintmaterial onto the substrate, the contact of the mold with the imprintmaterial, the exposure, and the removal of the mold. Accordingly, it ispreferable to perform degassing at a timing outside the period in whichthe imprint material 8 is ejected to the substrate. The timing ofdegassing may be a timing of substrate change or lot change.

Moreover, the degassing may be performed when abnormal ejection occursand is detected. Furthermore, the degassing may be performed when theimprint apparatus is not operating. The degassing may be performed suchthat the pump 22 is stopped while the imprint step is performed and thedegassing is performed during maintenance of the apparatus or in a timeslot in which there is no substrate to be subjected to imprintprocessing. Moreover, the imprint apparatus or the ejection device maybe configured to have a timer function and perform degassing when acertain time elapses. Furthermore, the degassing may be performed inresponse to a programmed command from the imprint apparatus or theejection device.

As described above, the ejection head 10 is provided with thecirculation mechanism including the degassing unit. The ejection deviceand the imprint apparatus capable of suppressing ejection failures andbreakage of the mold can be thereby achieved.

Second Embodiment

The second embodiment of the present invention is described below withreference to the drawings. Note that, since the basic configurations ofthe embodiment are the same as those of the first embodiment, only thecharacteristic configurations are described below.

FIG. 5 is a cross-sectional view illustrating the ejection head 10 inthe embodiment. The ejection head 10 of the embodiment includes a valve55 in a pipe extending from the cover 52 of the degassing unit 50.Providing the valve 55 as described above allows the inside of the cover52 to be maintained in a reduced pressure state by closing the valve 55after the discharge of the gas in the cover 52. Since the reducedpressure state can be maintained as described above, degassing can beperformed for a certain period by operating the pump even in anenvironment without a discharge system as long as there is a powersupply.

For example, when the ejection head 10 is to be transported or stored,the gas inside the cover 52 is discharged and the valve 55 is closed tomaintain the space in the cover 52 in the reduced pressure state. Then,the degassing can be performed by connecting a battery to the pump 22and causing the pump 22 to operate. When the ejection head 10 is to beconnected to the imprint apparatus, it is only necessary to connect thedischarge duct to the coupling 53 and discharge the gas via the valve55.

FIG. 6 is a view illustrating a state where the ejection heads 10 of theembodiment are connected in parallel to be stored. When the ejectionheads 10 are stored, as illustrated in FIG. 6, a degassed state of themultiple ejection heads 10 can be maintained by discharging the gas inthe cover 52, closing the valve 55, and connecting power supply cables57 to the multiple ejection heads 10 in parallel. The degassing statecan be thereby maintained in the multiple ejection heads 10.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2018-003497 filed Jan. 12, 2018, which is hereby incorporated byreference wherein in its entirety.

What is claimed is:
 1. An ejection device comprising: an ejecting unitfor ejecting an imprint material to which a pattern of a mold istransferred by bringing the mold into contact with the imprint material;and a containing unit including a first space containing the imprintmaterial and a second space separated from the first space by a flexiblemember, the first space communicating with the ejecting unit, whereinthe containing unit includes: a first opening which communicates withthe first space; a second opening which communicates with the firstspace; a connecting unit for allowing the imprint material to movebetween the first opening and the second opening; a pump unit, providedin the connecting unit, for moving the imprint material between thefirst opening and the second opening; and a degassing unit, provided inthe connecting unit, for collecting gas dissolved in the imprintmaterial.
 2. The ejection device according to claim 1, wherein theconnecting unit includes filter unit capable of filtering out a foreignobject contained in the imprint material.
 3. The ejection deviceaccording to claim 2, wherein the pump unit moves the imprint materialfrom the first opening to the second opening through the connectingunit, and the filter unit is provided downstream of the pump unit. 4.The ejection device according to claim 3, wherein a distance from thesecond opening to the ejecting unit is shorter than a distance from thefirst opening to the ejecting unit.
 5. The ejection device according toclaim 1, wherein the degassing unit is connected to openable andclosable valve unit.
 6. The ejection device according to claim 1,wherein the containing unit is connected to pressure control unitconnected to the second space and capable of controlling a pressure inthe second space.
 7. The ejection device according to claim 6, wherein apressure in the first space is controlled by controlling the pressure inthe second space.
 8. The ejection device according to claim 6, whereinthe containing unit and the pressure control unit are connected to eachother by a coupling.
 9. The ejection device according to claim 1,wherein the degassing unit is connected to pressure reduction unitcapable of reducing a pressure in the degassing unit via a coupling. 10.An imprint apparatus comprising: an ejection device including ejectingunit for ejecting an imprint material on which a pattern is formed bybringing a mold into contact with the imprint material and containingunit including a first space containing the imprint material and asecond space separated from the first space by a flexible member, thefirst space connected to the ejecting unit; and a processing devicewhich brings the mold on which the pattern is formed into contact withthe imprint material ejected from the ejecting unit, wherein thecontaining unit includes: a first opening which communicates with thefirst space; a second opening which communicates with the first space; aconnecting unit for allowing the imprint material to move between thefirst opening and the second opening; a pump unit, provided in theconnecting unit, for allowing the imprint material to move between thefirst opening and the second opening; and a degassing unit, provided inthe connecting unit, for collecting gas dissolved in the imprintmaterial.